Lightning-arrester



R. IVICNEILL.

LIGHTNING ARRESTEH..

APPLICATION FILED MAY/4,1920. LSBZTQ. @atentedune 28, 3921.

I I fx1 @i ,vn-pv PATENT oFFicE.

RALPH MONEILL, 0F NEWARK, NEW JERSEY.

LIGHTNING-.ARRESTER Specification of Letters Patent.

Patented June 28, 1921.

Application led May 4, 1920. Serial No. 378,844.

To all whom it may concern:

Be it known that I RALPH MONEILL, a citizen of the United btates and a resident of Newark, in the county of llssex and State of New Jersey, have invented an Improvement in Lightning-Arresters, of which the following description, in connection with the accompanying drawin s, is a specification, like characters on the rawings representing like parts.

This invention relates to electric circuit devices and more particularly, though not exclusively, to protector devices such as lightning arresters.

' One object of the invention is to provide a protective device such as a lightning arrester having normally spaced electrodes, adapted to protect not only against the h ightension discharges of atmospheric electricity but also against discharges from pcwer circuits where the current may fpersist for a substantial period. In case o a discharge through the arrester arising, for example, from a crossed power line, the resulting arc established between the electrodes may be required to carry considerable current until the line fuse blows. During the period of current flow, excessive heat is apt to be generated in the arrester and the latter presents a fire-hazard condition. The herein-described embodiment of the invention comprises a lightning arrester which may be of the vacuum type and which presents nor- Inally spaced electrodes, the arrester being so constructed that, n response to the effect of the current flow itself, they are caused to approach each other and eliminate or minimize the arc, but may be restored to their normally separated positions, so that the subsequent utility of the arrester is not impaired. Preferably, as herein, the restoration of the electrodes is automatic and is accomplished by the cessation of current flow or b the diminution of heat in the arc.

T e invention will be best understood by reference to the following description when taken lin connection with the accompanying illustration of one specific embodiment thereof, while its scope will be moreparticularly pointed out in the appended claims.`

In the drawings:

Figure 1 is a central, cross-sectional elevation showing an arrester embodying one form of the invention;

yand 19 are assembled together to form "a D Fi. 2 is a modified form of arrester showingt e application of one form of the invention toa double gap arrester employing three electrodes;

Fig. Bis a diagram showing one way in which the arrester shown in Iig. 2 may be employed;

Fig'. 4.- shows an arrester employing still another form of the invention and responsive to the magnetic effects of the current;

and

Fig. 5 is a sectional detail showing the thermally responsive metallic supports for the electrodes employed in the arrester shown inFigs. 1 and 2.

Referring to the drawin s and more particularly to the specific germ of arrester shown in Fig. 1, this consists of the normally separated and herein ball-shaped electrodes 7 and 9 contained within a preferably vacuous space formed within the glass capsule or container 11. The electrodes are connected to and supported by leading-in wires 13 and 15 which pass through the opposite ends of the container, the Wires being connected externally to any suitable terminals, herein to the interior of the metallic shells 17 and 19 respectively, the latter constituting the terminals by which the arrester may be connected with any of the usual or wellknown switchboard connections customarily employed for this purpose.

The container 11 and metallic sleeves 1 7 single unit by any suitable means such as the cementitious insulating binder 21 which is utilized to cement the sleeves andv hold the parts in fixed relation.

The container may be of any suitable shape or size, the arrester in the drawings being provided with a container in the form of an elongated capsule, the leading-in wires passing through opposite ends thereof, whereat a tight seal is effected. After the parts have been assembled'within the capsule, the latter is preferably exhausted or partially exhausted by any suitable or usual exhaustion process to produce any desired degree of vacuum, the exhaustion taking place through a tubular opening at one end which is afterward sealed off, forming the tip 23.

To protect the container against the discharge which is apt to take place between the electrodes, an intermediate protector` or sheath 25 may be emplo ed, the same herein comprising an open-en e'd tube or sleeve of glass or other substance having preferably a. relativel high melting point and resting loosely an supported upon the electrodes 7 and 9.

In the form shown in Fig. l, one or both of the electrodes are normally located somewhat out of line with and at opposite sides of the axis of the container and are secured to the leading-in wires by thermally responsive connections 27, so that in response to the heat generated by a sustained arc the connections 27 will bend from the full line position shown and move into the dotted line position shown in Fig. l, thereby bringing the two electrodes into closer association and preferably into direct cont-act with each other. lVhile other thermally responsive devices may be employed, herein the connections 27 comprise supporting strips of duplex metal, provided by firmly attaching together two strips of metal having different coeflicients of expansion, as is shown in Fig. 5. For example. brass and nickel steel may be employed, or other suitable materials may be used having properly related coefficients of expansion. Under the infiuence of heat, the brass, or other strip having the greater coefficient of expansion, will expand to a greater degree than the steel, or other strip having the lesser coefficient of expansion. This will cause the duplex strip to assume a curvilinear shape, such as is indicated by dotted lines, causing the electrode supported by the end thereof to move away from the side on which the strip of greater expansion is located. These supporting strips may be secured to the leading-in wires so as to provide a substantially rigid support for the electrodes, maintaining them in a normally fixed and separated position. IVhen the arrester, however, is subjected to a sustained cross of a power circuit, the heat created by the are Will be conducted directly to the thermal supporting strips, causing them to bend and brlng the electrodes into contact, thereby eliminating the arc. This stops the arc and the source of the heat, but as soon as the arrester cools, the strips will resume their former shape, automatically restoring the electrodes to their normal positions. If the current still continues, the arc Will be restablished, the heat affain generated and the operation repeated. lilhen the condition Which causes the arc ceases the arrester is ready for its original service.

By offsetting the electrodes laterally with relation to each other and converting the differential expansion of the two metallic members of the thermal supporting strip into a bending movement ofthe strip, the electrode is caused to swing about the point of connection betvveen the thermal strip and the 1eading-1n Wire and a substantial movement 0f the electrode secured from a very slight expansion of the metal, thereby making the device sensitively responsive to the heat of the arc.

In Fig. 2 there is shown a slightly different form of arrester employing three electrodes but operating upon substantially the same principle as that already described. The vacuous container 29 is provided at one end with the sealed-in leading-in wire 3l connected to the fixed electrode 33 and at its opposite end with the sealed-in leading-in wires 35 and 37, connected to the movable electrodes 39 and 4l respectively. The two electrodes 39 and 4l are normally separated from the electrode 33 but are attached to the leading-in wires 35 and 37 by the thermally responsive, duplex, metallic strips 43 and 45 respectively, in such a manner that, when heated, either one Will move to the dotted line position shown, causing its electrode to bridge the gap and contact with the fixed electrode 33. The electrodes may be surrounded by the protecting sleeve or envelop 46.

One application of this device is shown in Fig. 3 where the device to be protected is indicated at 47 and is included within the circuit 49, the latter provided with the fuses 5l and 53. The arrester is connected between opposite sides of the circuit 49 through the connection 55 which is electrically connected to the electrode 39 and the connection 57 which is electrically connected to the electrode 41. The fixed electrode is grounded, as shown.

The invention is not limited to any specific form of thermally responsive device for eliminating the arc or bringing the electrodes into closer association, nor is it limited to a device which responds directly to the heating effect of the arc. Such device may be made to respond directly to the effect of the current flow itself and in Fig. 4 there is shown a form of lightning arrester in which the electrodes are caused to approach by the magnetic action of the current and not by its heating effect.

In the form shown in Fig. 4, one or both of the leading-in Wires 59, after passing through the vacuous container 61, is given a coiled shape to form amagnetic coil 63, the end of the coiled Wire being secured to a small iron core 65, the latter connected to the electrode 67 by the short connecting Wire 69. This forms, in effect, a solenoid magnet such that in response to the current flow there is created a tendency to move the core and its attached electrode axially toward the center of the container, causing the electrodes to approach or come into contact. The electrode supports, including the coils, are structurally stiff enough to maintain the electrodes normally separated by a fixed space or gap, but the coils are suficently elastic t0 vides a protecting device with spaced electrodes, adapted to relieve the line of a static or atmospheric electricity but also providing protection against the heating effect of a prolonged arc by causing closure of the gap between the electrodes when an' arc-creating condition arises, but restoring the electrodes to their availability for their original service as soon as the condition is removed.

While I have herein shown and described for purposes of illustration one specific embodiment of the invention, it isto be understood that extensive deviations may be made therefrom without departing from the spirit thereof.

Claims:

1. An electric rotective device having normally separate electrodes movable relatively toward each other in response to the passage of a prolonged, arc-creating current, with provision for automatically separating said electrodes on the cessation of the current.

2. An electric protective device Vhaving normally separated electrodes, a container therefor, means adapted to cause relative approach o f the electrodes in response to the heat created. by an arc and to again separate them on the elimination of the arc.

3. An electric protective device having separated electrodes and a chamber therefor, said device being characterized by the provision of means to suppress a. prolonged arc due to a sustained current discharge, while leaving the arrester, after the cessation of the discharge, in normal, arc-creating relation to subsequent discharges.

4. A lightning arrester comprising a container and electrodes normally separated by a gap, the electrodes being bodily movable toward each other in response to the passage of a current through the gap.

5. An electric protective'device comprisving separated electrodes and a container, means responsive to the heat of an arc due to a current discharge to reduce the` arc but to restore the arrester after the cessation of the discharge in normal, arc-creating relation to subsequent discharges.

6. An electric protective device .comprising electrodes separated by a gap. a container and means responsive to thelieat of an arc to short-circuit the electrodes but to open the gap on the cessation of the heat.

7. An electric protective device comprising normally separated electrodes, a container therefor, leading-in circuits for each electrode, one of said circuits including a thermally responsive member movable under conditions of heat to cause its electrode to approach the associated electrode'.

8. An electric protective device comprising normally separated electrodes, a container and a differential expansion element responsive to the heat of an arc to cause relative alpproach of the electrodes.

9. n electric protective device having relatively movable and normally separated electrodes supported and positioned to approach by a swinging movement of an electrode about its support and a differential expansion member responsive to heat to move the electrodes relatively toward veach other.

10. An electric protective device having relatively movable and normally separate electrodes, one'I of said electrodes being supported by a differential eX ansion element and positioned to approac yits associated electrode by the bending of said-element.

11. An electric circuit device comprising electrodes separated by a gap, each with circuit connections, a container for said electrodes and means responsive to the passage of a prolonged, arc-creating current to cause said electrodes to contact withv each other While permitting their separation on the cessation of the current. Y Y

12. An electric circuit device comprising electrodes separated by a gap, a vacuous container therefor, circuit connections for the electrodes and thermally responsivev means to cause said electrodes relatively to approach and recede.

13. The method of protecting an electric V'circuit against extraneous current discharges which consists in providing a grounded circuit including a normally open gap, minimizing the abnormal heating effect of a prolonged are through said gap by reducing the gap and restoring the gap after the termination of the abnormal heated condition..

14. An electric protective device comprising a vacuous container withl leading-in wires, movable .separated electrodes within the container, and an electrode support adapted in response to a condition of heat to move this electrode toward its associated electrode.

Y 15. The combination with an electric circuit of a. protective device to protect the saine from extraneous current discharges, said device comprisinga vacuous container. leading-in wires therefor, electrodes within the container normally separated by a gap, one electrode being connected tothe circuit to be protected and the other heilig grounded, said electrodes having provision to cause RALPH MGNEILL. 

